Make Regex for special characters - regex

Question

I am trying to make it so that I have a UITexField that returns false when checked by a method if it has anything but letters in it, I have tried to create a RegEx, but have not been able to get it to work.
func checkNames(name: UITextField, text: UILabel) -> Bool {
let regEx = "[,./-=+}{[]`~'!#£$%^&*():;?0-9]"
let regExTest = Predicate(format:"SELF MATCHES %#", regEx)
let charResult = regExTest.evaluate(with: name.text)
if name.text != nil && charResult == false {
text.textColor = UIColor(red: 124, green: 252, blue: 0)
return true
} else {
text.textColor = UIColor(red: 255, green: 0, blue: 0)
name.text = nil
name.placeholder = "Alphabetical Name Required"
return false
}
}
I want it to return false if it has anything but letters.